“If this continues, people won’t take up their grazing rights and food production will fall. I keep 10 cattle on Uwch Gwerfai common, where people often walk: I’m now thinking of removing them.”

In recent months there has been a spate of high-profile cases. Last month, Warrington vet Liz Crowsley was killed by a herd of cows in Yorkshire. She was walking with dogs when the cattle turned on her.

David Blunkett, the former home secretary, was injured by a cow while out with his guide dog in the Peak District. And last month a police inspector won £10,000 in an out-of-court settlement after being crushed by 30 cows while walking his dog on the Sussex Downs.

But the case that has got farmers jittery was heard at Preston Crown Court this month. It ruled Cumbrian farmer John Cameron liable for injuries sustained by businesswoman Shirley McKaskie, 54, who, in 2003, was attacked by cattle and their calves while walking her dogs near her home in Penrith.

Mr Cameron found her unconscious and rushed her to his farmhouse on his quad bike. She later needed emergency brain surgery.Š

Mr Cameron has said he will appeal the judgement, which also leaves him with legal costs of more than £100,000.

In the aftermath, some legal experts opined that farmers could no longer risk keeping cattle in fields crossed by footpaths. The NFU gave the idea short-shrift, arguing that, with millions of walkers, the risks were miniscule.

What’s the truth? The Preston verdict, delivered by Judge Nigel Howarth, does not set a precedent, but may be influential in other hearings.

“In legal terms, as a first instance decision, the case is only persuasive as an authority; it is not a binding precedent,” said Nina Winter, the NFU’s chief legal adviser. “Other judges hearing similar cases are not bound to follow this decision.”Š

Judge Howarth held Mr Cameron liable under the Animals Act 1971 after the court heard it was characteristic of cows with calves to be aggressive, especially towards dogs – and people with dogs.

Ms McKaskie strayed from the designated right of way, but only because the footpath was blocked by nettles.

Mr Cameron’s claim that she was trespassing, and thus beyond legal protection, was over-ruled – and, in any case, there were no signs to indicate the path’s correct route.

The defendant claimed Ms McKaskie knew there may be cows in the field. Ultimately however, the court agreed she had not consented to the risk that the cows might attack her.

After the case, lawyers acting for Ms McKaskie warned that farmers will in future “have to be more careful” about where they put their cattle.

But NFU Cymru president Dai Davies stressed the case should be looked at maturely and in perspective. He said only a tiny minority experience dangerous encounters with cows.

On right-to-roam land the situation is less clear. Mr Griffiths, a former police officer, asked the county council to erect warning signs on Uwch Gwyrfai common. “The council wouldn’t because it didn’t want more “urban clutter” in the countryside,” he said.